- Bandwidth is the key factor in networking. Bandwidth is the throughput capacity of an electronic pathway such as a network link. It is measured in bits per second (Mbits/sec, Mbps) or bytes per second (MBytes/sec, MBs).
- Bandwidth monitoring system is a crucial aspect of professional server management for any network administrator. It helps to track bandwidth usage, to guarantee predictable ISP billing, and to prevent flooding issues. Bandwidth monitoring system core components are the SNMP protocol and monitoring software.
- SNMP (Simple Network Management Protocol) is a set of network communication specifications that cover all the basics of network management. It is a simple and expandable protocol designed to give the capability to remotely manage networking devices by polling and setting special counters values.
- Monitoring software periodically reads SNMP counters from networking devices. Monitoring software accumulates these samples continuously and then displays these statistics as HTML graphs - the most suitable live visual representation of network bandwidth utilization.
- 95th percentile is the smallest number that is greater that 95% of the numbers in a given set. Most ISPs use this method for data measuring because it provides a very accurate picture of the cost of the bandwidth. See detailed explanation here.
- MRTG (Multi Router Traffic Grapher) is unique, smart and very compact monitoring software that allows you to graph bandwidth utilization as well as several other metrics.
- ISP (Internet Service Provider) is an organization that provides access to the Internet. ISPs offers a wide range of Internet access methods such as Ethernet, DSL, T1/T3, ISDN, wireless, cable, or Satellite. Ethernet and DSL are widely used and most important.
- DSL (Digital Subscriber Line) is a network connection technology that uses the same wires as a regular telephone line and offers a data throughput speed up to 9 Mbps. DSL is a general term referring to different variations of this technology such as ADSL, HDSL, VDSL and RADSL.
- Ethernet, Fast Ethernet, and Gigabit Ethernet. These are one of the most important technologies in contemporary networking. Ethernet was invented in 1973 and it has become the most widespread LAN technology in use since the 1990s. Original Ethernet (10Base-T standard) worked at 10mbps speed. A newer version of Ethernet, called Fast Ethernet, supports data transfer rates of 100 Mbps, and the newest version, Gigabit Ethernet supports data rates of 1 gigabit (1000 megabits) per second. Due to its distance limitations Ethernet has long been used only in LANs (Local Area Networks). But these days with introduction of optic-fiber-based networks that removed these limitations, many ISPs provide Internet access over Ethernet links.
- BGP (Border Gateway Protocol) is one of the core routing protocols in the Internet. It works by maintaining a table of IP networks or 'prefixes' which designate network reachability between AS (autonomous systems). Most Internet users do not use BGP directly. However, since most Internet service providers must use BGP to establish routing between one another, it is one of the most important protocols of the Internet.
- AS (Autonomous System) is a collection of routers sharing the same routing policies and running under a single technical administration.
- Load balancing is the capability to divide traffic over multiple network links or servers. Load balancing is especially important for networks where it's difficult to predict the number of requests that will be issued to a server. Busy web sites typically employ two or more web servers in a load balancing scheme.
- Redundancy in bandwidth terminology means stability achieved by providing alternate paths for the traffic (links or routes) in case of failure.
- Traffic filtering is a general security term describing the process of analyzing all traffic and discarding undesirable data. Traffic filtering is generally performed in a router or in a firewall.
- Flooding detection refers to detection of various denial-of-service (DOS) network attacks that saturate a critical resource (bandwidth, CPU time), leading to system failure. Such an assault on a network that floods it with so many additional requests that regular traffic can either overload the server or cause it to crash.
- Traffic shaping is a system of controlling the speed of internet traffic.
Traffic shaping deals with concepts of classification of network traffic and
traffic prioritization policies.
- Router is the crucial device that let messages and all other data flow between networks. Router also connects two local area network (LAN) segments, which use similar or different architectures. The router is the only device that sees every message sent by any computer on either of the company's networks. Based on internal routing tables, routers read each incoming packet and decide how to forward it.
- Switch is another fundamental part of many networks because they speed things up. In networks, it's a device that filters and forwards packets between LAN segments. Switches operate at the data link layer and sometimes at the network layer and therefore support any packet protocol. LANs that use switches to join segments are called switched LANs or, in the case of Ethernet networks, switched Ethernet LANs.
- Firewall is a system designed to prevent unauthorized access to or from a private network.
All messages entering or leaving the network pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.
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